Secondly, even if we found larger samples size distinguishing BRCA 1 from BRCA 2 mutation carriers, information that can be drawn are still insufficient, not allowing definitive conclusions especially in BRCA 2 population.
Additionally, we depend on a sufficiently large sample size to distinguish statistically significant signals from the rest.
A power analysis shows that none of these studies used adequate sample sizes to distinguish genetic from shared environmental influences as a cause for familial aggregation.
The multilocus model is effectively indistinguishable from the single-locus model for small to medium sample sizes, as distinguishing 7.82% from 8.52% of left-handers in the offspring of R × R parents with a power of 80% would require 24,034 parent offspring pairs.
Data from Portugal indicate that smaller clutch sizes might be observed in southern Europe Variability and uncertainty due to sample size cannot be distinguished in detail, but sample sizes and comparable ranges indicate that data are reliable.
As shown in Figure 2, for a set of baseline error rates and assumed differences, the sample size required to distinguish groups quickly becomes large at 80% power.
The sample size needed to distinguish MCI from dementia was not estimated as a significant difference between the Q mci and the SMMSE would not be expected [ 15].
Many studies on the subject of depression and diabetes have methodological limitations such as lack of control group, small sample size, and failure to distinguish between type 1 and type 2 diabetes (10, 14).
To demonstrate the relative importance of the fast phase (over sample size), Vuong's test correctly distinguished a slower decaying exponential distribution as exponential rather than power law.
We have therefore only included studies with a sample size calculation and we have distinguished between results that were assessed as primary and secondary end points to limit the influence of chance findings in secondary end points.
